I – Integumentary System

Publisher Summary This chapter discusses integumentary system. Different components of the skin, including keratinocytes, dendritic cells, monocytes, lymphocytes, mast cells and vascular endothelial cells, can form the primary target for cutaneous toxicity. The skin may also exhibit alterations that are manifestations of systemic pathological processes. The skin functions in a unique way as an immunological organ, in which keratinocytes, Langerhans cells and T-lymphocytes form an integrated system mediating cutaneous immunosurveillance. Increased pigmentation (hyperpigmentation) of the human skin results from treatment with a number of systemically administered drugs. The chapter explores classifications of skin tumours. A wide variety of different tumour types have been described under these general headings in man, particularly those showing various types of differentiation toward epithelial appendages. Tumour subtypes showing a variety of epithelial differentiation patterns are observed in aged rodents, but they have been generally less well categorized. Although soft tissue neoplasms show some interspecies variation, there are fewer differences between the soft tissue tumours occurring in the usual experimental species and man than has commonly been supposed. This chapter concludes that despite advances in knowledge of the role of skin in the modulation of cutaneous immune responses, it may not be possible to predict the occurrence of adverse drug-induced skin reactions in man, based on animal models. Such reactions may only become evident in large-scale clinical trials, or in general clinical practice following marketing of novel agents.